Artificial teeth



A1,621,643 March .22 1927' w. T. SMITH ARTIFICIAL TEETH Filed Feb. 9,. 1925 itatented Mar. 22, 1927.

tl E@ S'iTES tenera rarer rice.

ARTIFICIAL TEETH.

Application led February 9, 1925. Serial No. 7,911.

rlhis invention relates to an improvement in artiticial teeth more particularly intended for plate or bridge work, and has for its object to provide an improved tooth compris ing a porcelain body and a metal backing on the lingual side of the tooth, these parts to be secured together by cement. and in such a manner that they will be strongly attached, while the inetal backing is preferably provided with a Harige or apron which covers the joint at the shouldered portions of the attached parts so as to prevent the secretions of the mouth trom coming in Contact with the cement at the joint between these shoulders and thereby injuring or disintegrating the cement, as is likely to occur, at times, with .artificial teeth as at present constructed.

In the accompanying drawing Fig. 1 is a side view ot the improved tooth, and Fig. 2 is a back view thereof. Fig. 3 is a central vertical section of' the improved tooth and its backing. Fig. 4L is a perspective view of the backing. Fig. 5 is a cross section on line 5-5, Fig. 3, and Fig. 6 is a view of the porcelain body of the tooth.

Referring to the drawing, 12 denotes the porcelain body portion of the toot-h which is provided with a central vertical recess 13, which is undercut at one end, and with a shoulder 14. The metal backing 15, which is preferably of' gold, has a facing part which fits against a flat surface on the porcelain part 12, the .said backing being preferably provided with a plain dowel pin 15, which tits in one part of the recess 13, and with a` hooked dowel pin 17 adapted to enter the undercut portion of the recess 13. The dowel pins 16 and 17 are preferably rounded, as shown more clearly in Fig. fl, so that the converging front walls of the correspondingly shaped vertical recess in which they fit will have a holding engagement with said pins, as clearly shown in Fig. 5. This metal backing has a shoulder 18 which fits against the shoulder 111 on the porcelain part 12, and, surrounding said shoulder 1 8, there Y is a flange or apron 19 which covers the joint between the said shoulders 14 and 18 and thus serves as a guard to prevent the entrance of saliva to the joint at these shoulders, thereby avoiding injury to or disintegration of the cement, by which the parts 12 and 15 are secured together, by the secretions of the mouth.

The shoulders 14 and 18 are preferably slightly inclined, as shown in Fig. 3, so that in fitting the partsftogether, after the cement has been applied to the contacting surfaces of these parts, there will be a slight wedgmg .action in forcing the hooked dowel pin 17 into the undercut part ot the recess 13 in the body part 12. rlhese slightly inclined shoulders are, however, not positively necessary, as the parts can be litted together in engaging the hooked dowel pin 17 in the undercut part of the recess 13 if the contacting shoulders 14e and 18 be formed straight or level.

From the foregoing it will be understood that the invention provides an artificial tooth comprising a porcelain body portion and a metal backing or lingual part of such construction that the two parts will be firmly secured together, while the joint between the contacting shouldered portions of these parts will be protected from disintegrating action by the saliva in the mouth of the wearer.

Having thus described my invention l claim and desire to secure by Letters Patent:

1. An artificial tooth comprising a porcelain body part having a shoulder and a central vertical recess with an undercut portion at the end ot said recess opposite said shoulder, combined with a backing part provided with two dowel pins arranged to enter and fit in said recess, one of said dowel pins having a hooked partto fit in said undercut portion of said recess in said porcelain body, said backing part having a shoulder corresponding to the said shoulder oi the said porcelain part.

2. An artificial tooth comprising a porcelain body part having a shoulder and a central vert-ical recess with an undercut portion at the end of said recess opposite said shoulder, combined with a backing part provided with two dowel pins arranged to enter and fit in said recess, one of said dowel pins having a hooked part to fit in said undercut portion ot said recess in said porcelain body, said backing part having a shoulder corresponding to the said shoulder of the said porcelain body, and said backing having also a flange or apron servingl to cover the joint at the shoulders of said parts.

3. An artificial tooth comprising a porcelain body part having a shoulder and a central vertical recess with an undercut portion at the end of said recess opposite said shoulder, combined with a backing part provided with two dowel pins arranged to enter and sponding to the said shoulder of the said porcelain part, said shoulders being slightly inclined to effect a slight Wedging action when said hooked doWel pin is being fitted into said undercut part of said recess.

4. An artificial tooth comprising a porcelain body part having'an inclined shoulder and a central vertical recess with an undercut portion at the end of said recess opposite said shoulder, combined with a backingpart provided With two rounded dowel pins arranged to enter said recess, one of said dowel pins having a hooked part to fit in said undercut portion oit' said recess, said backing part having an inclined shoulder corresponding to the said shoulder of the said porcelain part, and said backing part having also a flange or apron serving to cover the joint at the shoulders of said parts.

ln testimony whereof l afiix my signature.

VLMER T. SMITH. 

